Data Systems use data communication networks to exchange data. Typically, a data communication network, hereinafter called network, has transmission paths interconnecting nodes each coupled to data systems and each arranged to write data generated by an originating data system onto the network transmission paths and to read data received on the network transmission paths and addressed to a destination data system off the network.
These networks oftentimes use a token signal which is continuously transmitted on the network transmission paths to sequentially arrive at each node. In order to control the traffic flow on the network and to prevent one node from continuously transmitting data on the network thereby denying other nodes access, each node is inhibited from writing data onto the network until the node receives the token signal. When a node receives the token signal, the node is thereby enabled to write data onto the network exclusive of all other nodes. A problem arises in these networks in that the token signal is sometimes inadvertently lost. This may occur because of transient or equipment failures either in the nodes or transmission paths, or both, and results in an operational failure in that data systems are unable to write data onto the network thereby rendering the network inoperative until such time as the network location wherein the token signal was lost is identified.